RosettaCodeData/Task/Roman-numerals-Encode/Forth/roman-numerals-encode-1.fth

19 lines
816 B
Forth

: vector create ( n -- ) 0 do , loop does> ( n -- ) swap cells + @ execute ;
\ these are ( numerals -- numerals )
: ,I dup c@ C, ; : ,V dup 1 + c@ C, ; : ,X dup 2 + c@ C, ;
\ these are ( numerals -- )
:noname ,I ,X drop ; :noname ,V ,I ,I ,I drop ; :noname ,V ,I ,I drop ;
:noname ,V ,I drop ; :noname ,V drop ; :noname ,I ,V drop ;
:noname ,I ,I ,I drop ; :noname ,I ,I drop ; :noname ,I drop ;
' drop ( 0 : no output ) 10 vector ,digit
: roman-rec ( numerals n -- ) 10 /mod dup if >r over 2 + r> recurse else drop then ,digit ;
: roman ( n -- c-addr u )
dup 0 4000 within 0= abort" EX LIMITO!"
HERE SWAP s" IVXLCDM" drop swap roman-rec HERE OVER - ;
1999 roman type \ MCMXCIX
25 roman type \ XXV
944 roman type \ CMXLIV